It may be of importance to locate or track a user when the user is inside a building. However, a well-known outdoor positioning system employing a global positioning system (GPS) or any other satellite based system may not work inside a building due to lack of reliable reception of satellite coverage. Therefore, a positioning technique utilizing Earth's magnetic fields (EMF) indoors has been developed as one possible option for indoor location discovery. This type of location discovery applies, for example, a magnetic field strength measured by a positioning device. However, problems are related to this type of location estimation, especially in how to detect a change in the operational environment and how to initialize the positioning device for applying the EMF based positioning technique, for example.